Wire connector structure

ABSTRACT

A wire connector assembly including a fastener and a clip providing four wire gripping arms is disclosed. The arms are symmetrically positioned about a hole in the base of the clip through which the shank portion of the fastener extends to the terminal base plate. The clip is formed of a metal having sufficient stiffness to hold the fastener in place when it is initially assembled contacting the head portion of the fastener against the aRms. Upon final installation of lead wires, the head portion of the fastener compresses the wire gripping arms against the lead wires as the fastener is tightened into position.

United States Patent 1 Them 1 Aug. 8, 1972 [54] WIRE CONNECTOR STRUCTURE 996,107 12/1951 France ..339/246 Inventor: Edward G- Them, Mansfield, France S [73] Assignee: Thermo-Q-Disc, Incorporated, Manprimary Examinerajoseph Mcglynn Sfield ohm Att0rney-McNenny, Farrington, Pearne and Gordon [22] Filed: Feb. 11, 1970 [21] Appl. No.: 10,512 [57] ABSTRACT A wire connector assembly including a fastener and a [52] USCL 339/95 R 339/246 339/263 clip providing four wire gripping arms is disclosed. [51] Int. CL H0 9/10 The arms are symmetrically positioned about a hole in 58 Field ofSearch.2111222889/98 E o 568 266 269 the base 0f clip hmugh which the shank Pmtio 33:9/271" of the fastener extends to the terminal base plate. The clip is formed of a metal having sufficient stiffness to [56] R f r Cited hold the fastener in place when it is initially assembled contacting the head portion of the fastener against the UNITED STATES PATENTS aRms. Upon final installation of lead wires, the head 2,690,545 9/1954 Hubbell ..339/246 Portion of the fastener compresges the wire ppi 1,699,211 1/1929 Rose ..339/246 arms against the lead wires as the fastener is tightened 1,991,669 2/1935 Hausman ..339/246 into position- I l 7 Claims, 5 Drawing Figures FOREIGN PATENTS OR APPLICATIONS 847,427 9/1960 Great Britain ..339/263 BACKGROUND OF THE INVENTION single terminal is disclosed.

Although the present invention is generally useful for any electrical wire connection, and should not be otherwise limited, it will be described hereinafter with reference to electrical terminal connections such as those found on thermostats or the like.

PRIOR ART In the manufacture of electrically controlled devices, a variety of wire connectors has been developed to facilitate the final installation of lead wires to the terminals by the customer. Although a number of considerations exist with respect to each particular installation, generally each wire connector is designed to provide a secure electrical connection in a minimum amount of time. The importance of the production time consumed in the connection of lead wires is fully appreciated when it is considered that hundreds of thousands of electrical control devices having multiple connections may be installed by a single customer within one year. Thus, if a few seconds may be saved in the installation of each lead wire, the reduction in production costs is quite significant.

A variety of wire connectors which must be initially connected to the lead wire has been developed; however, these are not entirely satisfactory for several reasons. Initially, a separate wire connector is required for each lead wire and each wire must be individually attached to the connector. These disadvantages alone impose an unduly large expense upon the customer with respect to material costs and production time. Also, where multiple connections to a single terminal are required, the use of such connectors would be cumbersome, if not impractical. In addition, since the connectors of this type generally form a closed loop, the fastener or terminal screw must be entirely backed out of the terminal or initially shipped separately and completely installed by the customer. Reference may be had to US. Pat. Nos. 2,748,368 to Gookin, 2,461,994 to Merkel, and 2,326,100 to Lavarack et al. Thus, the closed loop configuration of the wire connector requires additional assembly time and imposes an additional expense upon the customer.

The prior art has also provided a number of wire connectors which are not initially attached to the lead wire, for example, those disclosed in US. Pat. Nos. 480,152 to Tobey and 355,423 to Watkins. These connectors are not entirely satisfactory either, since they provide only a single connection site which must be oriented with respect to the terminal. In addition, the wire connectors must be held in position so that they will not rotate as the terminal screws are tightened. The wire connector disclosed by Jackson in US. Pat. No. 2,231,316 has disadvantages similar to those described above with respect to the Tobey and Watkins devices. The Jackson device also provides only a single wire connecting site and, similarly, it must be held in position as the terminal screw is tightened.

As indicated above, an additional problem associated with many prior art devices exists with respect to the placement of the terminal screw in the appropriate terminal by the thermostat manufacturer. lt is desirable that the terminal screw be initially inserted in the appropriate terminal, as opposed to separate ship ment of the screw. If the screws are shipped separately, the customer must expend additional assembly time in locating, unpackaging and installing the terminal screw. Since a single thermostat may have as many as four terminals, this is a costly operation for the customer and should be avoided if possible. However, most wire connectors of the prior art do not permit the terminal screw to be initially placed in the terminal without completely tightening the screw down. This was necessary since the screw would otherwise vibrate loose during shipment and possibly be lost. Therefore, the customer was obligated to loosen or back out each screw before he could make the lead wire connections. This also is a time-consuming and costly operation in view of the fact that there are as many as four terminals per thermostat, and because there may be a number of thermostats on a single completed unit. Consequently, the wire connectors of the prior art provided the customer with one or the other of the above alternatives, neither of which satisfactorily solved the problem.

SUMMARY OF THE INVENTION The present invention provides a wire connector assembly for use in forming electrical wire connections. The assembly has fourwire gripping arms having arcuate configurations which encircle and firmly grip the wires.

The arms are symmetrically located so that the wire connector assembly may be automatically assembled by machine-fed operations. Since the four arms are symmetrically located, the clip may be oriented in any one of four symmetrical positions so as to provide an identical assembly structure. In addition, the arms have sufficient stiffness to hold the fastener or terminal screw in place when the connector is initially assembled by the manufacturer. Thus, the customer merely inserts the lead wire or wires into the arcuate-shaped arm and tightens the fastener.

The structure is also shaped so that the assembly coacts with the surface of the supporting structure. Therefore, the assembly is fixed against rotation and it does not have to be manually held in position as the fastener is tightened.

In the illustrated preferred embodiment, the wire connector assembly provides a fastener or terminal screw including an axially extending shank portion and a head portion having a greater radial dimension. The assembly also includes a clip having a base portion with a centrally located aperture through which the shank portion of the terminal screw extends and wire gripping arms positioned symmetrically about the periphery of the clip. The reversely bent arms project laterally from the base portion of the clip and then extend towards the shank portion of the fastener at a location spaced axially from the base. The arms do not extend past the near peripheral extremities of the :shank; however, they do terminate within the axial projection of the head portion of the terminal screw.

When the connector assembly is initially installed, the terminal screw is inserted and tightened until the top portion of the screw contacts and semi-compresses the arms of the clip. Thus, the clip effectively acts as a lock washer holding the screw in place during shipment, preventing it from vibrating out and being lost. Since the wire connector of the present invention permits the terminal screws to be initially installed by the manufacturer, they do not have to be separately shipped and installed by the customer, as was done in many instances in the past.

In addition, the assembly is designed so that the arms may be initially compressed to hold the screw in place, as described above, without necessitating the removal or backing out of the screw when the lead wires are subsequently connected. Therefore, the customer merely inserts the lead wire into the wire gripping arm and tightens the terminal screw. As the screw is tightened, the arm is compressed tightly against the lead wire and a secure connection is assured.

Since multiple wire gripping arms are provided, a number of lead wires may be easily connected to a single terminal. In addition, since each arm and connection is mechanically independent, any one wire in a multiple connection can be removed without disconnecting and reconnecting the other wires.

Further advantages will appear from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a typical thermostat with a wire connector according to this invention mounted thereon;

FIG. 2 is an enlarged, fragmentary plan view of the wire connector shown in FIG. 1, with parts removed for purposes of clarity;

FIG. 3 is a side elevation in cross section taken along the line 3-3 in FIG. 2, with parts broken away for clarity;

FIG. 4 is a cross-sectional view, similar to FIG. 3, illustrating the connection of two lead wires according to the present invention; and

FIG. 5 is a fragmentary plan view, illustrating another embodiment of a wire connector according to this invention.

DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a typical thermostat provided with a wire connector assembly 12 in accordance with this invention. The wire connector assembly 12 includes a fastener or terminal screw 14 and a clip 16. The screw 14 extends through the clip 16 and connects to a metal threaded terminal plate 18 provided on the thermostat 10. The plate 18 at the rearward portion of the thermostat 10, as shown in FIG. 1, is illustrated before a connector assembly 12 is installed thereon. The screw 14 is connected to an identical plate 18 lying below the clip 16, as more clearly shown in FIGS. 3 and The clip 16 includes a base portion 20 and wire gripping portions or arms 22. The base portion 20 includes an aperture or hole 24 through which the screw 14 extends in order to connect with the plate 18. The base portion 20 of the clip 16 may be provided with any shape arranged to fit against the adjacent surfaces of the thermostat 10. In the embodiment illustrated in FIGS. 1 through 4, the base portion 20 is essentially planar and fits against the planar surface 26 of the thermostat 10. In this embodiment, as illustrated in FIG. 2, the base portion 20 is substantially rectangular and extends radially beyond the wire gripping portions 22, providing edges 28 which abut the walls 30 and 32 of the thermostat 10. In this manner, the clip 16 is fixed against rotation and the terminal screw 14 may be tightened or loosened without manually holding the wire connector in position to prevent it from rotating.

The wire gripping portions or arms 22 of the clip 16 are best illustrated in FIG. 3. Each arm 22 comprises a lower portion 22a, an intermediate portion 22b which extends substantially perpendicular to the base portion 20, and a reversely bent portion 220 which extends towards the shank portion 34 of the screw 14. The arm 22 terminates adjacent the near radial extremities of the shank portion 34 and within the axial projection of the head portion 36 of the screw 14.

The head portion 36 of the screw 14 provides a lower surface 37 having an axially extended skirt 38 adjacent to its periphery which engages the arms 22. Therefore, as the screw 14 is tightened into the plate 18, the skirt 38 located at the outer radial portions of the lower surface 37 initially contacts the arms 22. The arms 22 are proportioned so that a vertical center line AA of a lead wire is radially inward from the outer edge of the skirt 38. As shown in FIG. 4, the zone of contact between the arms 22 and the skirt 38 extends to the left of the vertical center line AA. Consequently, as the screw 14 is tightened, the lead wire is securely encircled by the arm 22 below the surface 37 of the head portion 36, and is not forced in a radially outward direction. As shown in FIG. 4, a lead wire or wires, such as lead wires 40 and 42 are securely positioned below the head portion 36 of the screw 14 when it is tightened into the threaded terminal plate 18 The wire gripping enclosure is generally defined by the inner surface of the arm 22, the upper surface of the base 20, and the shank portion 34 of the screw 14. As shown in FIG. 3, the mechanical gripping of a lead wire by the arm 22 is enhanced by the serrations 44 on the inner surface of the arm 22. In this particular embodiment, approximately 60 serrations per inch at a depth of about 0.005 inch has been found satisfactory. The arm is formed of a material having sufficient hardness so that the serrations will effectively bite into the wire.

In Fig. 5, another embodiment of the present inven- .tion is illustrated. As there shown, a wire connector clip 46 having an essentially circular base portion 48 and wire gripping portions or arms 50 are employed with a thermostat 52 which is similar to the thermostat 10 illustrated in FIG. 1. The base portion 48 has a centrally located aperture or hole 54 similar to that provided in the base portion 20 of the clip 16. However, in this embodiment, the arms 50 radially project beyond the base portion 48 so that they coact with the walls 56 and 58 of the thermostat 52 and thereby fix the clip against' rotation.

Referring once again to FIG. 3, as indicated above, the screw 14 may be initially positioned so that the lower surface 37 of the screw contacts the arms 22 of the clip 16. The arms 22 are sufficiently stiff that when the terminal screw 14 is initially installed, it can be tightened a sufficient amount to prevent it from vibrating loose without significant bending of the arms. The semi-compressed arms, abutting the terminal screw, act in effect as a lock washer, preventing the screw from vibrating in or out and possibly being lost during shipment. Thus, the wire connector of the present invention permits the terminal screws to be initially installed by the manufacturer. Therefore, the terminal screws do not have to be separately packaged, shipped and subsequently installed by the manufacturer, as had been done in many instances in the past. Consequently,

neither this costly step nor its alternative, as described below, is imposed upon the manufacturers customer.

In addition, since the enclosure cross-sectional area is still larger than that of the lead wire, a lead wire can be inserted and the terminal screw subsequently tightened to secure the connection without first backing the screw out.,As indicated above, in the past, the terminal screws were usually either shipped separately or were tightened securely so that they would not be lost, making it necessary to loosen them or back them out before a lead wire could be connected. The wire connector assembly of the present invention avoids these problems, as it permits the terminal screw to be'initially installed in the terminal and the final lead wire connections to be made by simply inserting a lead wire in the provided enclosure and tightening the terminal screw. Therefore, the customer's assembly time and costs are significantly reduced, as the lead wires may be rapidly inserted and the terminal screw quickly tightened by a power driven screwdriver, for example.

Since the arms of the clip are compressed by the terminal screw as it is tightened into the terminal plate, the wire gripping enclosure is initially provided with a cross-sectional area significantly greater than that of the lead wire. Thus, a single clip is initially shaped so as to accommodate a range of wire sizes. For example, a single clip is designed so as to accommodate from No. 14 through No. gauge wire. Similarly, a variety of different size terminal screws is employed, such as a No. 6, No. 8, or No. I0 screw. Consequently, a single clip size is satisfactory for a wide range of applications encountered by the manufacturer and his customer.

Since each clip provides multiple arms or connection sites, a number of wires are easily connected to the same terminal. In addition, the clip is structured so that it may be employed with either single strand or multiple strand wire.

As shown in FIG. 2 and FIG. 5, the aperture through the base portion of the clip is centrally located and the arms are symmetrically positioned about the aperture. Therefore, the clip is correctly orientated with respect to the terminal in any one of the four symmetrical positions. Consequently, the clips may be automatically machine fed, and the arms will be properly positioned for subsequent lead wire connections. Thus, it is not necessary to accurately orientate the wire connector of the present invention with respect to wire connection sites and the terminal, as was necessary with many prior art devices.

The wire connector assembly of the present invention also facilitates the removal of a single wire from a terminal having multiple wires connected to it. Since each wire is connected to a separate arm, any wire may be removed without disturbing or disconnecting the other wires.

In some instances, the clip is formed of an elastic material in order to additionally facilitate theremoval of a wire. In this instance, the clip will undergo elastic deformation and as the screw is tightened, the arms will be elastically compressed against the lead wire. Therefore, when a wire is to be removed, the screw is simply loosened so as to pennit the arms to release the wire.

As best illustrated in FIG. 2, the wire connector assembly is also particularly useful where a wire is subjected to an exceptionally large: mechanical tension load. In this instance, the internal arms located at the upper and right sides of the clip, as shown in FIG. 2, are utilized. Such arms can be used even when the load on the wire tends to pull the arm out from under the screw head, since the walls 30 or 32 support the associated arm and prevent such movement.

Although preferred embodiments of this invention are illustrated, it is to be understood that various modifications and rearrangements may be resorted to without departing from the scope: of the invention disclosed.

What is claimed is:

1. A preassembled wire connector assembly adapted for subsequent wiring comprising a support formed with a threaded opening and a surface extending radially from said opening, a sheet metal clip formed of a resilient metal, said clip including a substantially flat base portion engaging said surface and provided with an aperture therein overlying said threaded opening, said clip also including at least one reversely bent resilient arm laterally extending from said base portion and having an intumed end extending back over said base portion at a location spaced therefrom on the side thereof opposite said surface, a headed screw extending through said aperture threaded into said opening, the head of said screw engaging said inturned end and resiliently deforming said arm from its unstressed position toward said base portion, said inturned end being spaced from said base portion by a distance greater than the diameter of the wire conductor to be connected whereby such wire can be positioned within said clip adjacent to said screw with a diameter of said wire held by said arm underneath the head of said screw, tightening of said screw causing such wire to be tightly clamped in said clip, said arm providing a resilient force against said head in the direction of said screw which produces a sufficient friction to prevent said screw from vibrating out of said threaded opening during handling of said assembly.

2. A wire connector assembly as set forth in claim 1, wherein said aperture is centrally located in said base portion.

3. A wire connector assembly as set forth in claim 2, wherein said clip includes at least four arms and said arms are symmetrically located about said aperture.

4. A wire connector assembly as set forth in claim 2, wherein said arms have a serrated interior surface.

5. A wire connector assembly as set forth in claim 2 wherein said support means is shaped to engage said clip and prevent rotation therebetween.

6. A wire connector assembly as set forth in claim 5 wherein said base portion extends radially beyond said arms to engage said support and thereby prevent said relative rotation between said clip and support.

7. A wire connector assembly. as set forth in claim 6,

wherein said wire gripping portion is fixed against radially outward movement by said support. 

1. A preassembled wire connector assembly adapted for subsequent wiring comprising a support formed with a threaded opening and a surface extending radially from said opening, a sheet metal clip formed of a resilient metal, said clip including a substantially flat base portion engaging said surface and provided with an aperture therein overlying said threaded opening, said clip also including at least one reversely bent resilient arm laterally extending from said base portion and having an inturned end extending back over said base portion at a location spaced therefrom on the side thereof opposite said surface, a headed screw extending through said aperture threaded into said opening, the head of said screw engaging said inturned end and resiliently deforming said arm from its unstressed position toward said base portion, said inturned end being spaced from said base portion by a distance greater than the diameter of the wire condUctor to be connected whereby such wire can be positioned within said clip adjacent to said screw with a diameter of said wire held by said arm underneath the head of said screw, tightening of said screw causing such wire to be tightly clamped in said clip, said arm providing a resilient force against said head in the direction of said screw which produces a sufficient friction to prevent said screw from vibrating out of said threaded opening during handling of said assembly.
 2. A wire connector assembly as set forth in claim 1, wherein said aperture is centrally located in said base portion.
 3. A wire connector assembly as set forth in claim 2, wherein said clip includes at least four arms and said arms are symmetrically located about said aperture.
 4. A wire connector assembly as set forth in claim 2, wherein said arms have a serrated interior surface.
 5. A wire connector assembly as set forth in claim 2 wherein said support means is shaped to engage said clip and prevent rotation therebetween.
 6. A wire connector assembly as set forth in claim 5 wherein said base portion extends radially beyond said arms to engage said support and thereby prevent said relative rotation between said clip and support.
 7. A wire connector assembly as set forth in claim 6, wherein said wire gripping portion is fixed against radially outward movement by said support. 